Transcript Mod 2
Mod 2 Slide Set 2 Survey of Animal Kingdom Introduction; Porifera-Nematoda See Mod 2 Learning Objectives at Blackboard Read Ch. 17 Do Ch 17 activities and quizzes at MasteringBiology Characteristics of Animals Multi-celled, heterotrophic, eukaryotes Require oxygen for aerobic respiration Reproduce sexually, and perhaps asexually Motile at some stage Develop from embryos Animal cells lack the rigid cell wall found in plant cells. Chordates 9 Major Phyla of Animals Porifera (sponges) Cnidaria (jellyfish, corals, etc) Platyhelminthes (flatworms) Nematoda (roundworms) Mollusca (mollusks) Annelida (segmented worms) Arthropoda (Bugs, crabs, etc) Echinodermata (starfish, etc.) Chordata (fish, tetrapods, etc.) Echinoderms Arthropods Annelids Coelomate Ancestry Mollusks Rotifers Roundworms Bilateral Ancestry Radial Ancestry Multicelled Ancestry Flatworms Cnidarians Sponges Single-celled, protistan-like ancestors Overview of the Animal Kingdom Another view of the A.K. Sponges No true tissues Cnidarians Radial symmetry Ancestral Protist Molluscs Flatworms Tissues Annelids Roundworms Arthropods Bilateral symmetry Echinoderms Chordates Animal Architecture supra-phyletic features (“above-the-phylum” features) LEVELS OF ORGANIZATION Animals range from simple to complex in their organization. • Cellular Level: (of organization) Sponges • Tissue Level: Cnidaria • Organ Level: Flatworms, Roundworms, Segmented worms, Molluscs, Arthropods, Echinoderms, Chordates Animal Architecture supra-phyletic features EMBRYOLOGICAL ARCHITECTURE Diploblastic or Triploblastic? 2 germ layers or 3 germ layers Acoelomate, No, false, or true… body cavity (coelom) Protostome or Deuterostome? Blastopore becomes mouth or it becomes anus. Symmetry Pseudocoelomate, Eucoelomate? None, Radial, Bilateral Segmentation a Eggs form and mature in female reproductive organs, and sperm form and mature in male reproductive organs. b A sperm and an egg fuse at their plasma membrane, then the nucleus of one fuses with the nucleus of the other to form the zygote. c By a series of mitotic cell divisions, different daughter cells receive different regions of the egg cytoplasm. d Cell divisions, migrations, and rearrangements produce two or three primary tissues, the forerunners of specialized tissues and organs. Gamete formation Germ Layers Fertilization frog sperm Cleavage Gastrulation midsectional views e Subpopulations of cells are sculpted into specialized organs and tissues in prescribed spatial patterns at prescribed times. Organ Formation top view f Organs increase in size and gradually assume specialized functions. side view Growth, tissue Specilazation Fig. 43-4, p.758 Generalized Embryological Development fertilization, zygote cleavage stages, 2, 4, 8, etc. morula (solid ball of cells) blastula (hollow ball of cells) with blastocoel (central cavity) gastrulation, gastrula archaenteron (gut) formation of germ layers •ectoderm •endoderm •mesoderm A gastrula Looks like this this hole is the blastopore p.769 Embryonic Germ Layers and the Tissues They Produce Ectoderm (“outer skin” the outer germ layer) Skin, Nervous system Endoderm Lining of digestive syst. Lining of lungs, etc Mesoderm Cardiovascular Bone Muscle, etc If an animal forms from an embryo of just 2 germ layers it is said to be diploblastic If an animal forms from an embryo of 3 germ layers it is said to be triploblastic Symmetry, radial or bilateral? Fig. 25-5, p.406 Radial vs Bilateral Symmetry The Gut none, saclike, or tubular? Region where food is digested and then absorbed. It can be a… Saclike gut: (the digestive system has one opening) One opening for taking in food and expelling waste. e.g. Cnidaria, Platyhelminthes Tubular gut: (the digestive system has two openings) Opening at both ends; mouth and anus e.g. Arthropoda, Chordata, Nematoda, Mollusca, Echinodermata, Annelida. The Body Cavity or Coelom acoelomate, pseudocoelomate, eucoelomate Segmentation Repeating series of body units Units may or may not be similar to one another Earthworms - segments appear similar Insects - segments may be fused and/or have specialized functions Annelida, Arthropoda, Chordata Segmentation (it evolved more than once; it must work pretty well !) sponges cnidarians flatworms coelom lost annelids mollusks roundworms coelom reduced pseudocoel arthropods echinoderms chordates coelom reduced molting radial ancestry, two germ layers true tissues multicelled body PROTOSTOMES mouth from blastopore DEUTEROSOMES anus from blastopore bilateral, coelomate ancestry, three germ layers Fig. 25-7, p.407 Segmentation arose early, Ediacaran Fossils, 600-500 myp Fig. 25-8a, p.407, Spriggina Fig. 25-8b, p.407, Dickinsonia Segmentation an early trilobite fire worm Fig. 25-8c, p.407 Segmentation Segmentation Segmentation Survey of the Major Animal Phyla Know these 9: PORIFERA CNIDARIA PLATYHELMINTHES NEMATODA MOLLUSCA ANNELIDA ARTHROPODA ECHINODERMATA CHORDATA Fig. 17-05 Sponges No true tissues Cnidarians Radial symmetry Ancestral Protist Molluscs Flatworms Tissues Annelids Roundworms Arthropods Bilateral symmetry Echinoderms Chordates Animal Origins Originated during the Precambrian (1.2 billion - 670 million years ago) From what? Two hypotheses: Multinucleated ciliate became compartmentalized Cells in a colonial flagellate became specialized Animal Origins 3. Choanocytes 1. Choanoflagellates 2. Proterospongia Volvox, a colonial green alga Animal Origins The peculiar flagellated collar cell is found in: 1. Choanoflagellates, single celled-Protists 2. Proterospongia, a colonial organism 3. Choanocytes of Sponges, a multi-celled animal Fig. 25-4a, p.405 Animal Origins Choanoflagellates a Unicellular Protist Fig. 25-4b, p.405 Animal Origins Proterospongia a colonial array of choanoflagellates around a central gelatinous matrix Fig. 25-4c, p.405 p.408 Phylum Porifera sponge1 sponge2 Widespread, benthic, sessile filter-feeders. w/ choanocytes ! Cellular level of organization No symmetry No tissues No organs all aquatic, mostly marine, a few live in freshwater. Reproduce sexually (and asex) Microscopic swimming larval stage Fig. 25-9a, p.408 Sponge Structure Cellular Organization can reproduce asexually by fragmentation Usually Sexual Reproduction Boring Sponge Fig. 25-9b, p.408 Glass Sponge Skeleton Tube Sponge Fig. 25-9c, p.408 Phylum Cnidaria mesogleafilled bell ”No head, no anus, no problem !” tentacles Radial Symmetry Tissue Level of Organization Diploblastic Mesoglea Sac-like Gut Stinging cells (nematocysts) Polyp and/or Medusa stages Fig. 25-13b, p.410 Two Main Body Plans POLYP stage usually asexual MEDUSA stage is sexual outer epithelium (epidermis) Polyp mesoglea (matrix) Medusa inner epithelium (gastrodermis) Fig. 25-12, p.410 Phylum Cnidaria nematocysts Only animals that produce nematocysts capsule’s lid at free surface of epidermal cell trigger barbed thread inside capsule nematocyst Fig. 25-13, p.410 Cnidarian Diversity 3 main groups… Scyphozoans (“cup animals”) (medusa is dominant stage, polyp is reduced) True Jellyfish Anthozoans (“flower animals”) (polyp stage only, no medusa) Sea anemones Corals Hydrozoans (“water animals”) (polyp is the dominant stage, medusa is reduced) Hydroids Fire Coral Portugese man o’ war Phylum Cnidaria: Coral Polyps Obelia Life Cycle (Hydrozoan) reproductive polyp male medusa female medusa ovum sperm zygote feeding polyp polyp forming planula Fig. 25-15a, p.411 Reproduction in Hydra sp. Feeding in Hydra Sea anemone feeding on fish youtube Fig. 25-14a2, p.411 The Portugese man-o-war is a colonial hyrozoan. The painful/deadly box jellies of Australia are hydroza too. Fig. 25-14b, p.411 Flatworms: Phylum Platyhelminthes Acoelomate, bilateral, cephalized animals Organ Level of Organization All have simple or complex organ systems Most are oviparous hermaphrodites Flatworms are acoelomate, bilateral and have a saclike gut Planarian Organ Systems Flatworms have much more sophisticated organ systems than Cnidaria. Cnidaria are at the tissue level of organization while flatworms are at organ level of organization. Digestive System Nervous System Reproductive System Excretory System Fig. 25-16, p.412 Four Major Groups Turbellarians (Turbellaria) Flukes (Trematoda) • E.g. Chinese Liver Fluke, etc. Monogenea E.g. the Planaria, etc. Gyrodactylus Gyrodactylus Tapeworms (Cestoda) E.g. Beef tapeworm, fish tapeworm, etc. Fish tapeworm Planaria Chinese live fluke Many flatworms are parasites Shistosoma mansoni, the blood fluke Tapeworms are in Phylum Platyhelminthes Taenia saginata, the beef tapeworm proglottids a Larvae, each with inverted scolex of future tapeworm, become encysted in intermediate host tissues (e.g., skeletal muscle) scolex b A human, a definitive host, eats infected, undercooked beef which is mainly skeletal muscle d Inside each fertilized egg, an embryonic, larval form develops. Cattle may ingest embryonated eggs or ripe proglottids, and so become intermediate hosts c Each sexually mature proglottid has female and male organs. Ripe proglottids containing fertilized eggs leave host in feces, which may contaminate water and vegetation. Fig. 25-18, p.413 Proglottids (look like scolex segments but aren’t) Fig. 25-18e, p.413 Tapeworm Reproductive unit (proglottid) with skin removed Scolex Suckers and hooks Figure 17.13ba Roundworms (Nematoda) Vinegar eels C.elegans Vinegar eels2 youtube3 False coelom (pseudocoelom) Complete digestive system pharynx intestine false coelom eggs in uterus gonad anus muscularized body wall Fig. 25-27, p.419 Nematoda have a pseudocoelom and have a tubular digestive system with both mouth and anus pseudocoelom Many Nematodes are parasitic but many are free-living too. They are perhaps the most abundant animals on Earth. A square meter of sediment or soil can contain millions. elegans “C. elegans” Dirofilaria immitis dog heartworm Ascaris Anisakis “the sushi worm” Enterobius vermicularis “pinworms” Wuchereria bancrofti (elephantiasis) Caenorhabditis The Nobel Prize in Physiology or Medicine 2002 The Nobel Assembly at Karolinska Institutet has awarded the Nobel Prize in Physiology or Medicine jointly to Sydney Brenner, Robert Horvitz and John Sulston for their discoveries concerning "genetic regulation of organ development and programmed cell death".By using the nematode Caenorhabditis elegans as a model system, the Laureates have identified key genes regulating these processes. They have also shown that corresponding genes exist in higher species, including man.This year´s Nobel Laureates have identified key genes regulating organ development and programmed cell death in the nematode C. elegans. They have also shown that corresponding genes controlling these processes exist in humans. Dog Heart Worms Larvae in blood transmitted by mosquitoes Adults in pulmonary vessels and heart Ascaris worms Ascaris Adult worms live in the lumen of the small intestine. A female may produce approximately 200,000 eggs per day, which are passed with the feces . Unfertilized eggs may be ingested but are not infective. Fertile eggs embryonate and become infective after 18 days to several weeks , depending on the environmental conditions (optimum: moist, warm, shaded soil). After infective eggs are swallowed , the larvae hatch , invade the intestinal mucosa, and are carried via the portal, then systemic circulation to the lungs . The larvae mature further in the lungs (10 to 14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed . Upon reaching the small intestine, they develop into adult worms . Between 2 and 3 months are required from ingestion of the infective eggs to oviposition by the adult female. Adult worms can live 1 to 2 years. The Sushi Worm Wuchereria bancrofti “elephantiasis” transmitted by mosquitoes adults up to 2.5 inch Fig. 25-28c, p.419 Pinworms